The present invention relates to an illumination apparatus for emitting illumination light received from a plurality of portions out of a common portion, an exposure apparatus, and an exposure method and device manufacturing method.
In the prior art, an exposure apparatus is used in a photolithography process to manufacture devices, such as a semiconductor element, a liquid crystal display element, and a thin film magnetic head. In a manufacturing process that uses the photolithography techniques, a projection optical system uses illumination light to illuminate and transfer a pattern, which is formed on a mask and serves as an original image, onto a plate to which a photosensitive agent such as photoresist is applied.
Due to the enlargement in the scale of liquid crystal elements or the like over these recent years, there is a demand for an exposure apparatus having an enlarged exposure region. Accordingly, a multi-lens exposure apparatus has been developed. The exposure apparatus transfers a pattern of a mask onto a plate, which is a photosensitive substrate, while synchronously moving the mask and the plate in a predetermined scanning direction relative to a plurality of projection optical units (for example, refer to Japanese Laid-Open Patent Publication No. 7-57986). The multi-lens exposure apparatus uses a plurality of light sources such as discharge lamps to ensure the exposure light intensity required for a large exposure region. The light from each light source is efficiently gathered by an elliptic mirror and used to illuminate the mask through, for example, an optical fiber bundle.